Encapsulation of inkjet heater chip for ion beam cross-section polishing and method of preparing chip cross-section sample
View Patent ↗A method for preparing an integrated circuit or micro-electro-mechanical system chip sample for ion cross-section polishing is provided. The method includes preparing a polymer coating formulation. The polymer coating formulation includes a novolac epoxy resin, a bisphenol-A/epichlorhydrin epoxy resin, a photoacid generator, an adhesion promoter, and a mixture of acetophenone, cyclohexanone and butyrolactone organic solvents. The integrated circuit or micro-electro-mechanical system chip sample is encapsulated by the polymer coating formulation, wherein the chip sample is then ready for ion beam cross-section polishing. A cross-section sample of integrated circuit or micro-electro-mechanical system chip is prepared by polishing the obtained polymer encapsulated integrated circuit or micro-electro-mechanical system chip with ion beam cross-section polisher. The disclosed method allows the cross-section sample to be obtained at a reduced polishing time. Moreover, a good quality and larger cross-sectional area of the sample is obtained, thus allowing for accurate inspection or analysis of the integrated circuit or micro-electro-mechanical system chip.
1. A method for preparing an integrated circuit or micro-electro-mechanical system chip sample for ion beam cross-section polishing, comprising the steps of:
preparing a polymer coating formulation comprising:
a novolac epoxy resin having an epoxide equivalent ranging from about 190 to about 250;
a bisphenol-A/epichlorhydrin epoxy resin having an epoxide equivalent of greater than about 1000;
a photoacid generator;
an adhesion promoter; and
a mixture of organic solvent including acetophenone, cyclohexanone and butyrolactone;
cleaning the integrated circuit or micro-electro-mechanical system chip sample to remove unnecessary components;
cleaving the integrated circuit or micro-electro-mechanical system chip sample to have the area of interest close to the cutting edge;
putting the integrated circuit or micro-electro-mechanical system chip sample in a metal tray on a hot plate;
heating the hot plate;
dropping the polymer coating solution onto the integrated circuit or micro-electro-mechanical system chip sample and shaking the metal tray to spread out the polymer coating solution on channels and surfaces of the integrated circuit or micro-electro-mechanical system chip sample;
keeping the integrated circuit or micro-electro-mechanical system chip sample heated on the hot plate to expel voids and remove residual solvents in the polymer coating;
irradiating the integrated circuit or micro-electro-mechanical system chip sample with an ultraviolet light to cure the polymer coating; and
removing the integrated circuit or micro-electro-mechanical system chip sample from the metal tray.
2. The method of claim 1 , wherein the polymer coating formulation comprises:
about 13.18 percent by weight of novolac epoxy resin;
about 13.18 percent by weight of bisphenol-A/epichlorhydrin epoxy resin;
about 2.93 percent by weight of photoacid generator;
about 0.58 percent by weight of adhesion promoter;
about 2.93 percent by weight of butyrolactone solvent;
about 17.20 percent by weight of acetophenone solvent; and
about 50.00 percent by weight of cyclohexanone solvent.
3. The method of claim 1 , wherein the metal tray includes an aluminum tray.
4. The method of claim 1 , wherein the hot plate is heated at 100° C.
5. The method of claim 1 , wherein the dropping of the polymer coating formulation and shaking of the metal tray are repeated 3 to 5 times.
6. The method of claim 1 , wherein the integrated circuit or micro-electro-mechanical system chip sample is kept heated on the hot plate at 100° C. for 10 minutes to expel voids and remove residual solvents in the polymer coating.
7. The method of claim 1 , wherein the integrated circuit or micro-electro-mechanical system chip sample is irradiated with ultraviolet fight for 10 minutes.
8. The method of claim 1 , further including cleaning the excess polymer coating at edges and bottom of the integrated circuit or micro-electro-mechanical system chip sample being removed from the metal tray.
9. The method of claim 1 , wherein the micro-electro-mechanical system chip sample is a so heater chip of an inkjet printhead.
10. A method for preparing a cross-section sample of an integrated circuit or micro-electro-mechanical system chip, comprising the steps of:
preparing a polymer coating formulation comprising:
a novolac epoxy resin having an epoxide equivalent ranging from about 190 to about 250;
a bisphenol-A/epichlorhydrin epoxy resin having an epoxide equivalent of greater than about 1000;
a photoacid generator;
an adhesion promoter; and
a mixture of organic solvent including acetophenone, cyclohexanone and butyrolactone;
cleaning the integrated circuit or micro-electro-mechanical system chip sample to remove unnecessary components;
cleaving the integrated circuit or micro-electro-mechanical system chip sample to have the area of interest close to the cutting edge;
patting the integrated circuit or micro-electro-mechanical system chip sample in a metal tray on a hot plate;
heating the hot plate;
dropping the polymer coating formulation onto the integrated circuit or micro-electro-mechanical system chip sample and shaking the metal tray to spread out the polymer coating formulation on channels and surfaces of the integrated circuit or micro-electro-mechanical system chip sample;
keeping the integrated circuit or micro-electro-mechanical system chip sample heated on the hot plate to expel voids and remove residual solvents in the polymer coating;
irradiating the integrated circuit or micro-electro-mechanical system chip sample with an ultraviolet light to cure the polymer coating;
removing the integrated circuit or micro-electro-mechanical system chip sample from the metal tray; and
performing ion beam cross-section polishing.
11. The method of claim 10 , wherein the polymer coating formulation comprises:
about 13.18 percent by weight of novolac epoxy resin;
about 13.18 percent by weight of bisphenol-A/epichlorhydrin epoxy resin;
about 2.93 percent by weight of photoacid generator;
about 0.58 percent by weight of adhesion promoter;
about 2.93 percent by weight of butyrolactone solvent;
about 17.20 percent by weight of acetophenone solvent; and
about 50.00 percent by weight of cyclohexanone solvent.
12. The method of claim 10 , wherein the metal tray includes an aluminum tray.
13. The method of claim 10 , wherein the hot plate is heated at 100° C.
14. The method of claim 10 , wherein the dropping of the polymer coating formulation and shaking of the metal tray are repeated 3 to 5 times.
15. The method of claim 10 , wherein the integrated circuit or micro-electro-mechanical system chip sample is kept heated on the hot plate at 100° C. for 10 minutes to expel voids and remove residual solvents in the polymer coating.
16. The method of claim 10 , wherein the integrated circuit or micro-electro-mechanical system chip sample is irradiated with ultraviolet light for 10 minutes.
17. The method of claim 10 , further including cleaning the excess polymer coating at edges and bottom of the integrated circuit or micro-electro-mechanical chip sample being removed from the metal tray.
18. The method of claim 10 , wherein the micro-electro-mechanical system chip sample is a heater chip of an inkjet printhead.